Introduction of a concept of a flexible Ethernet provides a feasible evolution direction for virtualization of an Ethernet physical connection. Further, in the flexible Ethernet, one or more physical connections may be cascaded together in a specific sequence to constitute one physical connection group. The physical connection group is equivalent to a logical connection between a transmit end and a receive end, and interface bandwidth of the logical connection may be considered as a sum of bandwidth of all physical connections in the physical connection group. Therefore, according to an actual requirement, logical connections with different bandwidth may be configured in the flexible Ethernet by cascading different physical connections, and the flexible Ethernet is more flexible than a conventional Ethernet that depends on a physical connection.
In the flexible Ethernet, a transmit end allocates a data stream over a logical connection to each physical connection in a physical connection group for parallel transmission, and the transmit end allocates the data stream exactly according to a sequence of physical connections in the physical connection group, that is, in a specific period, when a physical connection is ranked first, a sub-stream allocated to the physical connection is also ranked first in an entire data stream. After receiving a sub-stream transmitted over each physical connection in the physical connection group, a receive end needs to assemble all sub-streams in the same sequence as the transmit end in order to restore the data stream over the logical connection. Therefore, in a process of parallel transmission of sub-streams, each physical connection in the group not only indicates an identifier to the receive end, but also identifies a sequence of all physical connections in the physical connection group for the receive end such that the receive end restores the data stream.
In order to identify a sequence of all physical connections in a physical connection group, multiple configuration interaction maps of the physical connection group are transmitted in an overhead area (a bit area included in an overhead code block) of each sub-stream. In this manner, much redundant information is transmitted, and resources in the overhead area are wasted. In addition, transmission of the multiple configuration interaction maps of the physical connection group takes a long time, thereby resulting in low transmission efficiency.